intrigued by python signal capabilities [async]

gistfile1.py

"""Got intriged with signal capabilities (http://docs.python.org/2/library/signal.html)

I define simple ``asyncall`` function thats takes numner seconds and deffered function (similar window.setTimeout(n_ms, func/code_literal))
    >>> asyncall(5, lambda *args: say('A'))
    >>> asyncall(10, lambda *args: say('B'))
    >>> asyncall(2, lambda *args: say('C'))
    C
    A
    B

Then only a liitle more complex:

    async_clock = lambda i: asyncall(i, lambda *args: xtime())
    >>> async_clock(2)
    Thu Mar  7 02:03:26 2013  # after 2sec 

    >>> map(async_clock, [1, 2, 3, 4, 5])
    [None, None, None, None, None]
    Thu Mar  7 02:03:28 2013
    Thu Mar  7 02:03:29 2013
    Thu Mar  7 02:03:30 2013
    Thu Mar  7 02:03:31 2013
    Thu Mar  7 02:03:32 2013

That is only an experiment of aving async calls without forking/threads.
It lacks:
- non-unix support
- ms resolution
- sys.getrecursionlimit() as its how its mimics the stack  
- it has only apporx sec accuracy
- kill acync task ``clearTimeout``

So DONT use it! More likely you will like to use:
- quees speeking like celery (http://www.celeryproject.org/) 
- http://docs.python.org/2/library/threading.html#timer-objects
"""

import sys, signal, time
import math

  
def asyncall(nsec_later, handler):
    prev_handler_eta = int(math.ceil(signal.getitimer(signal.ITIMER_REAL)[0]))
    if prev_handler_eta:
        prev_handler = signal.getsignal(signal.SIGALRM)
        # reshedule and mimic stack, see sys.getrecursionlimit()
        delta = prev_handler_eta - nsec_later
        resheduled_for = min(prev_handler_eta, nsec_later)
        if delta == 0:
            new_handler = lambda *args: prev_handler(*args) or handler(*args)
        elif delta < 0:  
            new_handler = lambda *args: prev_handler(*args) or asyncall(abs(delta), handler)
        else:
            new_handler = lambda *args: handler(*args) or asyncall(abs(delta), prev_handler)
        signal.signal(signal.SIGALRM, new_handler)
        signal.alarm(resheduled_for)
    else:                    
        signal.signal(signal.SIGALRM, handler)
        signal.alarm(nsec_later)


def say(x):
    print x
    sys.stdout.flush()
    
		
def xtime():
    print time.ctime()
    sys.stdout.flush()
    

its about to make the idea clear - not clever